Multifunction medical device and related methods of use

ABSTRACT

An embodiment of the invention may include a medical device. The medical device may include a flexible tube, an elongate member configured to cut tissue and extend from the flexible tube, and a cauterizing member configured to cauterize tissue and to move relative to the elongate member and the flexible tube. The cauterizing member may substantially surround at least a portion of the elongate member.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefits of priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application No. 60/831,920, filed Jul.20, 2006, for MULTIFUNCTION MEDICAL DEVICE AND RELATED METHODS OF USE,the entirety of which is incorporated herein by reference.

DESCRIPTION OF THE INVENTION Field of the Invention

A combined electro-cautery and electro-cutting device to be used inmedical procedures, and related methods of use.

Background of the Invention

Cancerous or benign lesions of the gastrointestinal tract often start inthe mucosal layer of the stomach or intestines. With improveddiagnostics and screening, such lesions are being identified prior toextension into the wall of the stomach or intestines. Removal of suchcancerous or benign lesions is desirable, preferably before theirextension into the wall of the stomach or intestines.

One method of removing such lesions includes an invasive surgicalresection of the lesion and the adjacent bowel. However, surgicalapproaches may cause trauma to the patient.

Another method of removing such lesions includes local excision of themucosal, for example, with access via natural orifices. A variety ofendoscopic instruments may be used in such a procedure.

One such instrument and method may include placing a chamber attached tothe end of an endoscope near a lesion, applying suction to the lesion soas to draw the lesion in the chamber, and then using an electrosurgicalsnare within the chamber to excise the portion of the lesion disposed inthe chamber. This may be done repeatedly to completely resect theaffected tissue.

Another such instrument and method may include advancing a grasper to alesion via a channel of an endoscope. The grasper lifts the lesion, andthen an electrosurgical snare is passed through another channel of theendoscope. The electrosurgical snare is placed around the shaft of thegrasper and is advanced to encircle the lifted tissue. The snare is thenactivated to excise the tissue.

Several other endoscopic instruments may be used in conjunction with oneor more of the above-referenced methods. For example, a needle may beused to inject saline or other solution under the mucosal to raise thelesion away from the underlying muscle wall so as to limit perforation.

Current upper gastrointestinal (UGI) endoscopic mucosal resection (EMR)procedures may utilize one or more endoscopic instruments in one or moresteps of the following sequence. First, a dye applicator may be used toidentify suspect tissue. Cautery may then be used to mark the lesionmargins. Injection, as described above, may be used to raise the mucosaltissue layer, followed by excision to remove the lesion, according toone of the above described methods, for example. A cautery may then beused to control bleeding due to the excised tissue. Irrigation may beused to cleanse the area where the lesion was excised. These endoscopicinstruments and steps may be used on multiple, time-consuming occasionsin a single resection procedure, which may require inserting andremoving each of these instruments on multiple, time-consumingoccasions.

SUMMARY OF THE INVENTION

In accordance with the invention, an embodiment of the invention mayinclude a medical device. The medical device may include a flexibletube, an elongate member configured to cut tissue and extend from theflexible tube, and a cauterizing member configured to cauterize tissueand to move relative to the elongate member and the flexible tube. Thecauterizing member may substantially surround at least a portion of theelongate member.

Various embodiments of the invention may include one or more of thefollowing aspects: the cauterizing member may be configured to movelongitudinally relative to the elongate member and the flexible tube;the elongate member may be configured to remain substantially stationaryin a longitudinal direction relative to the flexible tube; a handle mayinclude a first portion and a second portion; an elongate connectorconnecting the cauterizing member to one of the first portion and thesecond portion; movement of the first portion relative to the secondportion may move the cauterizing member relative to the elongate memberand the flexible tube; a cap connecting the elongate member to theflexible tube; the cap may define a first lumen configured toaccommodate the elongate connector therethrough; the cap and theelongate connector may be configured to cooperate so as to substantiallyprevent fluid flow through the first lumen of the cap; the elongateconnector may be configured to conduct current; the elongate connectormay be configured to be electrically connected to both of thecauterizing member and the elongate member; at least one configurationthe cauterizing member may be substantially surrounded by the flexibletube; a handle may include an electrical connector and a fluidconnector; the elongate member may include a lumen; the electricalconnector may be configured to be connected to a source of current andmay be configured to be electrically connected to both of thecauterizing member and the elongate member; and the fluid connector maybe configured to be connected to a source of fluid so as to providefluid to the lumen of the elongate member.

Another embodiment of the invention may include a medical device. Themedical device may include a flexible tube, an elongate memberconfigured to cut tissue, a cauterizing member configured to moverelative to the elongate member and the flexible tube, a handleconfigured to move relative to the elongate member and the flexibletube, and an electrical connector extending through the flexible tubeand configured to move substantially synchronously with the cauterizingmember and the handle relative to the elongate member and the flexibletube. The electrical connector may be configured to provide current toat least one of the elongate member and the cauterizing member.

Various embodiments of the invention may include one or more of thefollowing aspects: the cauterizing member may substantially surround atleast a portion of the elongate member; the elongate member may beconfigured to remain substantially stationary in a longitudinaldirection relative to the flexible tube; the handle may include a firstportion and a second portion; movement of the first portion relative tothe second portion may move the cauterizing member relative to theelongate member and the flexible tube; the electrical connector mayconnect the cauterizing member to one of the first portion and thesecond portion; a cap may connect the elongate member to the flexibletube; the cap may define a lumen configured to accommodate theelectrical connector therethrough; the cap and the electrical connectormay be configured to cooperate so as to substantially prevent fluid flowthrough the lumen of the cap; in at least one configuration thecauterizing member may be substantially surrounded by the flexible tube;the handle may include the electrical connector and a fluid connector;the elongate member may include a lumen; the electrical connector may beconfigured to be connected to a source of current and may be configuredto be electrically connected to both of the cauterizing member and theelongate member; the fluid connector may be configured to be connectedto a source of fluid so as to provide fluid to the lumen of the elongatemember; and the electrical connector may be configured to accommodatecurrent flow to only one of the elongate member and the cauterizingmember at any point in time.

A further embodiment of the invention may include a medical device. Themedical device may include a flexible tube defining a lumen, an elongatemember configured to cut tissue, the elongate member defining a lumenconfigured to accommodate fluid flow from the lumen of the flexibletube, a cauterizing member configured to move relative to the elongatemember and the flexible tube; and an electrical connector disposed inthe lumen of the flexible tube. The electrical connector may beconfigured to accommodate current flow to at least one of the elongatemember and the cauterizing member when the electrical connector may bein contact with fluid disposed in the lumen of the flexible tube. Theelectrical connector may consist of an electrically conductive material.

Various embodiments of the invention may include one or more of thefollowing aspects: the cauterizing member may be configured to movelongitudinally relative to the elongate member and the flexible tube;the elongate member may be configured to remain substantially stationaryin a longitudinal direction relative to the flexible tube; a handle mayinclude a first portion and a second portion; movement of the firstportion relative to the second portion may move the cauterizing memberrelative to the elongate member and the flexible tube; the electricalconnector may connect the cauterizing member to one of the first portionand the second portion; a cap may connect the elongate member to theflexible tube; the cap may define a lumen configured to accommodate theelongate connector therethrough; the cap and elongate connector may beconfigured to cooperate so as to substantially prevent fluid flowthrough the lumen of the cap; the electrical connector may be configuredto be electrically connected to both of the cauterizing member and theelongate member; in at least one configuration the cauterizing membermay be substantially surrounded by the flexible tube; a handle mayinclude the electrical connector and a fluid connector; the electricalconnector may be configured to be connected to a source of current; andthe fluid connector may be configured to be connected to a source offluid so as to provide fluid to the lumen of the elongate member and thelumen of the flexible tube.

Yet another embodiment of the invention may include a method of treatingtissue. The method may include providing a device including, a flexibletube, an elongate member configured to cut tissue, and a cauterizingmember configured to move to a first position and a second positionrelative to the elongate member and the flexible tube. The firstposition may be different from the second position. The method mayinclude positioning the cauterizing member in the first position suchthat the cauterizing member does not surround a portion of the elongatemember, with the cauterizing member in the first position, cuttingtissue via the portion of the elongate member, positioning thecauterizing member to the second position so as to substantiallysurround the portion of the elongate member, and with the cauterizingmember in the second position, cauterizing tissue via the cauterizingmember.

Various embodiments of the invention may include one or more of thefollowing aspects: longitudinally moving the cauterizing member relativeto the flexible tube; the device may further comprise a handle includinga first portion and a second portion and an electrical connectorconnecting the cauterizing member to one of the first portion and thesecond portion; moving the first portion relative to the second portionso as to implement the positioning steps; moving the electricalconnector via the movement of the first portion relative to the secondportion; providing current to one of the cauterizing member and theelongate member via the electrical connector; surrounding thecauterizing member with the flexible tube during the cutting step; theelongate member may include a lumen; the device may further comprise ahandle including an electrical connector and a fluid connector; themethod may further comprise providing a source of current and a sourceof fluid; connecting the fluid connector to the source of fluid so as toprovide fluid to the lumen; irrigating tissue via fluid flowing from thelumen; connecting the electrical connector to the source of current soas to provide a current to at least one of the cauterizing member andelongate member; and the elongate member may be configured to besubstantially stationary relative to the flexible tube.

A yet further embodiment of the invention includes a method of treatingtissue. The method may include providing a device including a flexibletube, an elongate member configured to cut tissue, a cauterizing memberconfigured to move relative to the elongate member and the flexibletube, a handle portion configured to move relative to the elongatemember and the flexible tube, and an electrical connector configured tomove substantially synchronously with the cauterizing member and thehandle portion relative to the elongate member and the flexible tube.The method may further include manipulating the handle portion so as tomove the electrical connector and the cauterizing member relative to theelongate member and the flexible tube, providing current to the elongatemember via the electrical connector, and providing current to thecauterizing member via the electrical connector.

Various embodiments of the invention may include one or more of thefollowing aspects: positioning the cauterizing member such that thecauterizing member does not surround a portion of the elongate memberand cutting tissue via the portion of the elongate member; positioningthe cauterizing member so as to substantially surround the portion ofthe elongate member and cauterizing tissue via the cauterizing member;longitudinally moving the cauterizing member relative to the flexibletube; the device may further comprise a handle including the handleportion and a second portion; moving the handle portion relative to thesecond portion so as to implement the positioning steps; surrounding thecauterizing member with the flexible tube during the cutting step; thedevice may further comprise a handle including the handle portion, theelectrical connector, and a fluid connector; the elongate member mayinclude a lumen; providing a source of current and a source of fluid;connecting the fluid connector to the source of fluid so as to providefluid to the lumen; irrigating tissue via fluid flowing from the lumen;connecting the electrical connector to the source of current so as toprovide a current to at least one of the cauterizing member and elongatemember; and the elongate member may be configured to be substantiallystationary relative to the flexible tube.

Still another embodiment of the invention may include a method oftreating tissue. The method may include providing a device including aflexible tube defining a lumen, an elongate member configured to cuttissue, the elongate member defining a lumen configured to accommodatefluid flow from the lumen of the flexible tube, a cauterizing memberconfigured to move relative to the elongate member and the flexibletube, and an electrical connector disposed in the lumen of the flexibletube, the electrical connector being in electrical connection with boththe elongate member and the cauterizing member, wherein the electricalconnector consists of an electrically conductive material. The methodmay further include flowing fluid through the lumen of at least one ofthe flexible tube and the elongate member and providing current to atleast one of the elongate member and the cauterizing member via theelectrical connector while fluid may be disposed in the lumen of theflexible tube and may be in contact with the electrical connector.

Various embodiments of the invention may include one or more of thefollowing aspects: positioning the cauterizing member such that thecauterizing member does not surround a portion of the elongate memberand cutting tissue via the portion of the elongate member; positioningthe cauterizing member so as to substantially surround the portion ofthe elongate member and cauterizing tissue via the cauterizing member;longitudinally moving the cauterizing member relative to the flexibletube; the device may further comprise a handle including a first portionand a second portion; the electrical connector may connect thecauterizing member to one of the first portion and the second portion;moving the first portion relative to the second portion so as toimplement the positioning steps; moving the electrical connector via themovement of the first portion relative to the second portion;surrounding the cauterizing member with the flexible tube during thecutting step; the device may further comprise a handle including theelectrical connector and a fluid connector; providing a source ofcurrent and a source of fluid; connecting the fluid connector to thesource of fluid so as to provide fluid to the lumen of the elongatemember; irrigating tissue via fluid flowing from the lumen of theelongate member; connecting the electrical connector to the source ofcurrent so as to provide a current to the at least one of thecauterizing member and elongate member; and the elongate member may beconfigured to be substantially stationary relative to the flexible tube.

Additional objects and advantages of the invention will be set forth inpart in the description which follows, and in part will be obvious fromthe description, or may be learned by practice of the invention. Theobjects and advantages of the invention will be realized and attained bymeans of the elements and combinations particularly pointed out in theappended claims.

The foregoing general description and the following detailed descriptionare exemplary and explanatory only and are not restrictive of theinvention, as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate embodiments of the invention andtogether with the description, serve to explain the principles of theinvention.

FIG. 1 is a perspective view of a medical device according to anembodiment of the present invention.

FIG. 1A is schematic view of a part of a proximal portion of the medicaldevice of FIG. 1 .

FIG. 1B is a cross-sectional view of the part of the proximal portionalong line Hof FIG. 1A.

FIG. 10 is a schematic view of another part of the proximal portion ofthe medical device of FIG. 1 .

FIG. 1D is a cross-sectional view of the another part of the proximalportion along line II-II of FIG. 10 .

FIG. 2 is a perspective view of a medial portion and a distal portion ofthe medical device of FIG. 1 in a first configuration.

FIG. 2A is a cross-sectional view of a part of the medial portion alongline III-III of FIG. 2 .

FIG. 3 is a perspective view of the medial portion and the distalportion of the medical device of FIG. 1 in a second configuration.

FIG. 3A is a cross-sectional view of a part of the distal portion alongline IV-IV of FIG. 3 .

FIG. 3B is a cross-sectional view of another part of the distal portionalong line V-V of FIG. 3 .

FIG. 4 is a perspective view of a distal portion of a medical deviceaccording to another embodiment of the invention.

FIG. 5 is a perspective view of a distal portion of a medical deviceaccording to a further embodiment of the invention.

DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to the present exemplaryembodiments of the invention illustrated in the accompanying drawings.Wherever possible, the same reference numbers will be used throughoutthe drawings to refer to the same or like parts.

FIGS. 1, 1A-1D, 2, 2A, 3, and 3A-3B depict an exemplary embodiment of amedical device 1. Medical device 1 may be configured to combineexcision, cautery, and irrigation features into a single device. Medicaldevice 1 may have the advantage of permitting all three procedures to beconducted without using multiple instruments and any associated problemsthat come with using multiple instruments, including device exchange,additional time for the procedure, additional trauma to the patient, andincreased cost.

Medical device 1 may include a proximal portion 100, a medial portion200, and a distal portion 300. The major components of the proximalportion 100 may include a handle 101, an actuator 102 movable relativeto handle 101, an electrical connector 103 connected to actuator 102,and an irrigation port 104 connected to handle 101. As shown in FIG. 2 ,for example, medial portion 200 may include, as its major components, anouter elongate member 201 or sheath, a middle elongate member 202 orcoil, and elongate wire connectors 203. Elongate connectors 203 mayconnect to actuator 102 and electrical connector 103. A lumen 202 c ofmiddle elongate member 202 may be in fluid communication with port 104.

The major components of distal portion 300 may include a cap 301, asheath 302, a capsule 303, a knife 304 and a tip 305 with an orifice306. Cap 301 may be disposed on an end of middle elongate member 202,and sheath 302 may be an extension of outer elongate member 201. Capsule303, which performs cautery, and knife 304, which excises tissue, mayhave power supplied to them by elongate connectors 203. In thisembodiment, a monopolar current may be provided to device 1.

Capsule 303 may move relative to cap 301, sheath 302, and knife 304,such that in a first configuration, a distal portion of knife 304 may becovered by capsule 303, and in a second configuration, the distalportion of knife 304 may be exposed to perform excisions. Orifice 306and a lumen 310 of knife 304 may be in fluid communication with lumen202 c of middle elongate member 202 for the supply of irrigation fluid.Tip 305 may be at a distal end of knife 304 to minimize perforation andassist in lifting target tissue for excision. Each of the variouscomponents of device 1, and their interconnection and function, will nowbe described in more detail.

FIGS. 2, 3, and 3A-3B depict an exemplary embodiment of distal portion300. Distal portion 300 may include various components to performexcision, cautery, and irrigation. As mentioned above, distal portion300 may include cap 301, sheath 302, capsule 303, knife 304, and tip 305with orifice 306.

Cap 301 may be coupled to a distal end of elongate member 202 at aproximal end of distal portion 300. Cap 301 may serve as a passage forelongate electrical connectors 203 and for irrigation fluid. Threelumens 301 a, 301 b, 301 c may extend through cap 301, as shown in FIG.3A. Each of lumens 301 a, 301 b, 301 c may have a circularcross-sectional profile and a longitudinal axis substantially parallelto a longitudinal axis of cap 301.

Lumens 301 a, 301 c may be configured to accommodate elongate connectors203 therethrough. Lumens 301 a, 301 c may have the same cross-sectionalareas and may be spaced symmetrically around lumen 301 b. Electricalconnectors 203 may have a cross-sectional shape and dimensionssubstantially similar to that of lumens 301 a, 301 c such that they forma tight fit. Accordingly, electrical connectors 203 may be in physicalcontact with cap 301 via lumens 301 a, 301 c and may provide current tocap 301. The tight spacing of electrical connectors 203 within lumens301 a, 301 c, while still allowing longitudinal movement of electricalconnectors 203 relative to lumens 301 a, 301 c, may substantiallyprevent or impede fluid from flowing through lumens 301 a, 301 c, forexample, from lumen 202 c to an area distal to cap 301.

Lumen 301 b may be configured to accommodate irrigation therethrough,for example, from lumen 202 c. Lumen 301 b may be substantially coaxialwith cap 301. In the embodiment shown, lumen 301 b may have a largercross-sectional area than each of lumens 301 a, 301 c. Lumen 301 b mayaccommodate irrigation and may provide irrigation to an end of interiorlumen 310 of elongate member 304.

Cap 301 may have a variety of alternative configurations, including, forexample, a different number of lumens. In addition, each of lumens 301a, 301 b, 301 c may have the same configuration (includingcross-sectional shape and/or area), or two or more of lumens 301 a, 301b, 301 c may have different configurations. Lumens 301 a, 301 b, 301 cmay be disposed on any portion of cap 301 in any desired configuration.For example, any one of lumens 301 a, 301 b, 301 c may be substantiallycoaxial with cap 301.

Sheath 302 may be configured to surround cap 301, capsule 303, and adistal portion of elongate member 304 that may be not exposed. Sheath302 may extend distally from cap 301 and may be made of an insulationmaterial, such as a rubber or polymer, to prevent a current from passingtherethrough. When sheath 302 surrounds at least the electricallyconductive portions of capsule 303, capsule 303 may be prevented fromeither contacting or passing a current to an area outside of outersurface 302 a of sheath 302. An outer surface 303 a of capsule 303 maycontact an inner surface 302 b of sheath 302 when sheath 302 is disposedaround capsule 303. Sheath 302 may be integral with, and an extensionof, outer elongate member 201 from medial portion 200 of medical device1. Capsule 303 may be longitudinally movable relative to sheath 302 soas to cause sheath 302 to cover and uncover capsule 303.

Sheath 302 may have a variety of alternative configurations, including,for example, being made of any suitable biocompatible material. A spacemay be present between an outer surface 303 a of capsule 303 and aninner surface 302 b of sheath 302 when sheath 302 is disposed aroundcapsule 303. Sheath 302 may be a separate piece attached to outerelongate member 201. Sheath 302 may be longitudinally movable relativeto one or more of cap 301, capsule 303, elongate member 304, tip 305,and/or orifice 306, for example, to cover and/or uncover one or more ofthose components.

Capsule 303 may be a cautery member that includes a first section 307, asecond section 308, and a third section 309, as shown in FIGS. 2 and 3 .First section 307 may be a proximal section, second section 308 may be amedial section, and third section 309 may be a distal section. Secondsection 308 may be a cautery segment and therefore may be comprised ofan electrically conductive material such as copper, stainless steel, orother metals. First and third sections 307, 309 may be insulationsegments and therefore may be comprised of nonconductive materials suchas a rubber, polymer, or ceramic. Second section 308 may be configuredto accommodate a current therethrough, and may be electrically connectedto elongate connectors 203 extending through lumens 301 a, 301 c of cap301. That connector may be made by a direct connection between secondsection 308 and elongate connectors 203, i.e., connectors 203 extendingthrough first section 307 to a proximal portion of second section 308.

Capsule 303 may be longitudinally movable relative to sheath 302. In afirst configuration, substantially an entirety of capsule 303, includingsecond section 308, may be covered by sheath 302. In a secondconfiguration, however, at least a portion of capsule 303 may cover theportion of elongate member 304 otherwise exposed and extending from theend of sheath 302. In this second configuration, a portion of capsule303; for example, second section 308, may not be covered by sheath 302,and a distal end of capsule 303 may contact a proximal portion of tip305, which may act as a distal stop against further distal movement ofcapsule 303. In such a configuration, capsule 303 may prevent elongatemember 304 from coming into contact with body tissue and/or passing acurrent from elongate member 304 to body tissue.

Capsule 303 may have a variety of alternative configurations, including,for example, sections 307, 308, 309 having any shape and/orconfiguration. Any combination of sections 307, 308, 309 may be acautery segments and insulation segments. As a further example, secondsection 308 may be indirectly connected to elongate connectors 203 viaintervening connectors. As an even further example, in the firstconfiguration, only a portion of capsule 303, for example, only firstsection 307 and second section 308, may be covered by sheath 302, and inthe second configuration, a portion of capsule 303 may still be coveredby sheath 302, and/or a space may separate a distal end of capsule 303from contacting tip 305. In another example, capsule 303 may betemporarily closed at either end in the configuration shown in FIG. 2 .For example, tip 305 may cooperate with a distal end of section 309 toclose the distal end of section 309 and prevent fluid from flowing intoan interior of capsule 303.

Elongate member 304 may be a cutting member made of a suitablebiocompatible material, such as stainless steel. Specifically, elongatemember 304 may be a hypotube. Elongate member 304 may be configured tocut issue, for example, by including one or more sharp edges. Elongatemember 304 may be affixed to lumen 301 b of cap 301, and elongate member304 itself may define a lumen 310, as shown in FIG. 3B, that may be inflow communication with lumen 301 b and orifice 306 to form anirrigation conduit. A source of current may be connected to elongatemember 304 via a part of medial portion 200, such as elongate connectors203, so as to pass a current through member 304.

The current may be passed through member 304 using any suitable methodand configuration. For example, elongate connectors 203 may be inelectrical communication with cap 301 via lumens 301 a, 301 c, which mayprovide power to elongate member 304.

Elongate member 304 may have a variety of alternative configurations,including, for example, a configuration of any suitable cutting member.Elongate member 304 may be made of any suitable material and by anysuitable method, and may be affixed to any portion of distal portion300. Elongate member 304 may be solid and not define a lumen 310, inwhich case the device either does not perform irrigation or irrigationmay be conducted by other means. The source of current may be anysuitable source of current, for example, a high-frequency generator. Asanother alternative, elongate member 304 may be configured to excisetissue without the use of electrical current. In some embodiments, aninner insulator may disposed on an inner surface of elongate member 304to insulate lumen 310, and the fluid flowing therethrough, from thecurrent passing through elongate member 304.

Tip 305 may be a safety tip at a distal end of elongate member 304. Tip305 may be configured to minimize perforation of tissue by a distal endof elongate member 304. Tip 305 may be configured to hook, lift, andposition tissue for excision, for example, as described herein. Tip 305may be made out of an insulating material, such as a rubber, polymer, orceramic, and has a substantially spherical shape. Tip 305 may define alumen leading to orifice 306.

Tip 305 may have a variety of alternative configurations. For example,tip 305 may be a safety tip made out of any suitable material having anysuitable shape and/or configuration, and may be placed on any suitableportion of distal portion 300. Tip 305 may be configured to minimizeperforation of tissue by any portion of distal portion 300. Tip 305 mayinclude a coating made out of an insulating material, such as a rubber,polymer, or ceramic. Tip 305 may be configured to lift tissue, forexample, folded tissue portions in the gastrointestinal tract.

Tip 305 may include an orifice 306 on its distal end. Orifice 306 may bein flow communication with the lumen of tip 305 and interior lumen 310of elongate member 304. Orifice 306 may be configured to allow fluidflow past the distal tip of elongate member 304 and tip 305. Orifice 306may be aligned with a longitudinal axis of elongate member 304 and tip305.

Orifice 306 may have a variety of alternative configurations, such asany suitable shape. Orifice 306 may be in flow communication with anysuitable source of fluid, such as saline, water, or other biocompatibleirrigation fluids. Orifice 306 may be disposed at any surface of tip 305to direct irrigation fluid in any suitable direction. For example,orifice 306 may be directed proximal to tip 305 so as to provide fluidto an area adjacent to elongate member 304 and/or capsule 303. Orifice306 may include a nozzle configured to control fluid flow, for example,the fluid flow's direction, velocity, and area of coverage.

FIGS. 1 and 1A-1D depict an exemplary embodiment of proximal portion100. As mentioned above, proximal portion 100 may include a handle 101,an actuator 102, an electrical connector 103, and an irrigation port104.

Handle 101 may include a thumb ring 105 and a guide shaft 106. Thumbring 105 may be integrally formed with guide shaft 106. Guide shaft 106may include a slot 110 extending therethrough configured to accommodateelongate connectors 203 and a portion of actuator 102 and connector 103,more specifically, second end 111 of connector 103.

Actuator 102 is shown in FIGS. 1 and 1A-1B. Actuator 102 may beconfigured to move relative to handle 101 by sliding relative to guideshaft 106. Actuator 102 may include finger rings 107 disposed aroundguide shaft 106. A user may be able to move actuator 102 relative tohandle 101 by placing fingers in thumb ring 105 and finger rings 107 andmoving the fingers relative to each other.

Actuator 102 may include a central portion 108 that has a centralthroughhole, or lumen, to accommodate shaft 106. Central portion 108, aswell as finger rings 107, shaft 106, and thumb ring 105, may be moldedfrom a suitable insulative material, such as a plastic. Central portion108 may accommodate structure configured to pass current therethrough,specifically, connector 103. Central portion 108 may prevent anelectrical current from passing from connector 103 and elongateconnectors 203 to other portions of actuator 102 and proximal portion100, such as thumb ring 105 and finger rings 107. Central portion 108may includes structure, such as cross pins, that extends into slot 110of handle 101 from both sides of slot 110 to maintain actuator 102 in aspecific rotational position relative to guide shaft 106. At least aportion of connector 103 may be substantially perpendicular to alongitudinal axis of guide shaft 106. Actuator 102 may be coupled to andconfigured to move capsule 303 longitudinally via elongate connectors203.

In various embodiments, actuator 102 may be an suitable actuator, may beconfigured to move relative to handle 101 in any suitable manner, andmay include one or no finger ring 107. For example, handle 101 andactuator 102 may take the form of a thumb ring and spool-type handleknown in the art. Actuator 102 may be coupled to and/or configured tomove capsule 303 using any suitable method. As another example, thumbring 105 may be separately formed from guide shaft 106 and thenattached.

Connector 103 may include a first end 109 configured to be connected toa high-frequency generator. Connector 103 may extend through centralportion 108 and may be connected at a second end 111, more specificallythe end disposed inside guide shaft 106 and actuator 102, to elongateconnectors 203, as shown in FIG. 1A Connector 103 may be made out of anysuitable material configured to pass current from the source of currentto elongate connectors 203, such as stainless steel or other metals.Second end 111 of connector 103 may extend into slot 110 of guide shaft106, as shown in FIGS. 1A and 18 . Connector 103 may be coupled to andconfigured to move capsule 303 via elongate connectors 203. In variousembodiments, connector 103 may be configured to be connected to anysuitable source of current and may have any suitable configuration.

Port 104 is shown in FIGS. 1, 1C, and 1D. Port 104 may be configured tobe connected to guide shaft 106 of handle 101 at a distal end 106 a ofguide shaft 106. Port 104 may define lumens 104 a, 104 b as shown inFIGS. 1C and 1D. Both lumens 104 a, 104 b may be configured toaccommodate fluid therethrough. Lumen 104 a may be disposedsubstantially parallel to and substantially coaxial with a longitudinalaxis of guide shaft 106. Lumen 104 b may be at an angle relative tolumen 104 a. For example, lumen 104 b may be disposed substantiallyperpendicular to the longitudinal axis of guide shaft 106 and/or lumen104 a. Lumen 104 b may have a connection portion 104 b-1 that may beconfigured to be connected to a source of fluid and form a substantiallyfluid tight seal with a connector of the source of fluid. Lumen 104 amay have a distal end 104 a-1 that may be configured to be connected toan irrigation lumen defined by a portion of medial portion 200, such aslumen 202 c of middle elongate member 202. Lumens 104 a, 140 b may beconfigured to accommodate fluid flow from connection portion 104 b-1 toa distal end 104 a-1.

Elongate portion 113 may be disposed within lumen 104 a. For example,elongate portion 113 may be a hypotube. Elongate portion 113 may extendfrom a distal end 106 a of guide shaft 106 to a distal end 104 a-1 oflumen 104 a. At a proximal end 104 c of port 104, a cross-sectional areaof lumen 104 a may narrow such that an inner diameter of proximal end104 c may be substantially similar to an outer diameter of elongateportion 113. In such a configuration, elongate portion 113 may be movedsubstantially longitudinally relative to portion 104. O-ring 114 may bedisposed in distal end 106 a of guide shaft 106 and may form asubstantially fluid-tight fit with both an outer surface of elongateportion 113 and an inner surface 106 b of guide shaft 106, and may stillallow elongate portion 113 to move longitudinally relative to lumen 104a and guide shaft 106. A combination of the tight fit between elongateportion 113, proximal end 104 c, and O-ring 114 may form a tight fit soas to impede or prevent fluid flow therethrough, for example, from lumen104 a to the area in guide shaft 106 proximal to proximal end 104 c.Connectors 203 may be disposed and/or integral with elongate portion113. For example, connectors 203 may extend through an entire length ofelongate portion 113 and may be attached to an inner surface of elongateportion 113. Connectors 203 may emerge from elongate portion 113substantially at distal end 104 a-1 of port 104.

FIGS. 2, 2A, and 3 disclose an exemplary embodiment of medial portion200. Medial portion 200 may include outer elongate member 201, middleelongate member 202, and elongate connectors 203.

Outer elongate member 201 (i.e., sheath) may be configured to beadvanced through a working channel of an endoscope having a diameter of,for example, about 2.8 mm. Outer elongate member 201 may be made out ofan electrically insulating, heat resistant, flexible material, such astetraflouroethylene, polyethylene, or polytetraflouroethylene. Outerelongate member 201 may have a substantially cylindrical configurationwhen outer elongate member 201 is substantially straight, and withsheath 302, may have a length sufficient to cover cap 301 and at least aportion of capsule 303 on the distal end, and extend to port 104 at theproximal end. A proximal end 201 a of outer elongate member 201 may beintegrally, formed with or otherwise connected to a distal end of port104, and a distal end 201 b of outer elongate member 201 may beintegrally formed with a proximal end 302 a of sheath 302. Outerelongate member 201 may substantially cover and may be affixed to middleelongate member 202 to define a lumen 202 c that accommodates elongateconnectors 203 and irrigation fluid.

Various alternative configurations may be also possible. For example,outer elongate member 201 may be configured to be advanced through aworking channel of an endoscope having any suitable diameter. Outerelongate member 201 may be made out of any suitable material, may haveany suitable configuration, and may have any suitable length. Forexample, outer elongate member 201 may have a length sufficient to covera portion of distal portion 300 and/or a portion of proximal portion100. Outer elongate member 201 may connect to and/or be integrallyformed with one or more portions of proximal portion 100 and/or distalportion 300. Alternatively, outer elongate member 201 may be separatefrom and connected to one or more portions of proximal portion 100and/or distal portion 300

Middle elongate member 202 may be a stainless steel coil that may beclosely wound, both to accommodate fluid flow therethrough and preventfluid flow from an inner surface of middle elongate member 202 to anouter surface of middle elongate member 202. Middle elongate member 202may be flexible so that it may pass through an endoscope channel andthrough tortuous anatomy. Middle elongate member 202 may be connected toportions of proximal portion 100 and distal portion 300. Specifically,middle elongate member 202 may be connected on a distal end to cap 301and on a proximal end 202 b to distal end 104 a-1 of port 104. Middleelongate member 202 may substantially cover elongate connectors 203, andmay define a lumen 202 c configured to accommodate elongate connectors203 therethrough. Lumen 202 c may also accommodate fluid flow betweenlumen 104 a of port 104 and lumen 301 b of cap 301. In alternativeembodiments, middle elongate member 202 may be made out of any suitablematerial and have any suitable configuration.

Medial portion 200 may include elongate connectors 203 such aselectrical wires. Elongate connectors 203 may be configured to conductcurrent to establish an electrical connection between a source ofcurrent, via connector 103, second section 308 of capsule 303, andelongate member 304. A proximal end 203 a of elongate connectors 203 maybe connected to a second end 111 of connector 103, and a distal end ofelongate connectors 203 may be connected to second section 308 ofcapsule 303 and elongate member 304. Elongate connectors 203 may bedisposed through lumens 301 a, 301 c of cap 301 and lumen 104 a of port104. Elongate connectors 203 may also be disposed within lumen 113 a ofelongate portion 113, and may be attached to elongate portion 113.Elongate connectors 203 may be longitudinally movable relative to cap301, elongate member 304, tip 305, orifice 306, outer elongate member201, middle elongate member 202, port 104, guide shaft 106, and thumbring 101. Elongate connecters 203 may be configured and coupled to movelongitudinally substantially synchronously with the movement of fingerrings 107, central portion 108, connector 103, and capsule 303. Elongateconnectors 203 may be configured to move capsule 303 proximally relativeto elongate member 304 and tip 305 into sheath 302, so as to exposeelongate member 304 and prevent capsule 303 from coming into contactwith tissue. Elongate connectors 203 also may be configured move capsule303 distally relative to elongate member 304 and tip 305 out of sheath302, so as to cover elongate member 304 and allow capsule 303 to comeinto contact with tissue. In the embodiments shown, elongate connectors203 are not covered by insulation.

In various embodiments, medial portion 200 may include any number ofelongate connectors 203, for example one connector. Connectors 203 maybe any suitable connectors made of electrically conductive material andeither covered or uncovered with insulation. For example, elongateconnectors 203 may be covered by an insulation material, such as rubberor plastic, so as to prevent current from flowing out of elongateconnectors to other portions of medical portion 200, such as middleelongate member 202. Elongate connectors 203 may be configured toconduct current between any portions of proximal portion 100 and/ordistal portion 300. For example, elongate connectors 203 may be indirect electrical communication with one or more of cap 301 and elongatemember 304. Elongate connectors 203 may be configured as thin filmconductors that may be incorporated in an electrically conductivematerial, for example, elongate portion 113.

Embodiments of the invention include methods of using medical device 1.In one example, medical device 1 and an endoscope may be provided. Theendoscope may be placed into a tortuous body lumen of a patient such asany portion of the gastrointestinal tract. The endoscope may be thenadvanced into the body lumen until a distal end of the endoscope may besubstantially adjacent to body tissue to be removed, such as a lesion.Medical device 1 may then be advanced down a working channel of theendoscope. Specifically, distal portion 300 may be first advanced downthe working channel of the endoscope, followed by medial portion 200.Medical device 1 may be continuously advanced until at least a part ofdistal portion 300 emerges from a distal end of the working channelsubstantially adjacent to body tissue to be removed.

At some point prior to or during the procedure, medical device 1 may beconnected to a source of current and a source of fluid. Specifically, asource of current may be connected to a first end 109 of connector 103so as to establish an electrical connection between connector 103,elongate connectors 203, capsule 303 (e.g., second section 308), andelongate member 304. A source of fluid may be connected to a connectionportion 104 b-1 of port 104 so as to establish a fluid connectionbetween the source of fluid and lumen 104 b, lumen 104 a, lumen 202 c,lumen 301 b of cap 301, lumen 310 of elongate member 304, and orifice306.

While medical device 1 may be advanced down the working channel of theendoscope, medical device 1 may be in a passive configuration. Noportion of medical device 1 has current running through it and noportion of medical device 1 includes fluid, or at least does not havefluid running through it. In the passive configuration, capsule 303 maybe in an advanced (i.e., distal) configuration and covers elongatemember 304 such that a distal end of capsule 303 may be in contact withtip 305. Some portions of capsule 303 may be covered by sheath 302(e.g., a proximal portion of first section 307) while other portions ofcapsule 303 may be exposed (e.g., a distal portion of first section 307and substantially all of second section 308 and third section 309).Along with capsule 303, one or more of elongate connectors 203,connector 103, finger rings 107, and central portion 108 may be in anadvanced configuration by being in a longitudinally distal positionrelative to shaft 106.

When medical device 1 may be disposed in the desired positionsubstantially adjacent to tissue to be removed, medical device 1 may beplaced into an active configuration at any point during the procedurewhen current or irrigation may be needed. To do so, first end 109 ofconnector 103 may be connected to a source of current so as to allowcurrent to flow through connector 103, elongate connectors 203, secondsection 308 of capsule 303, and elongate member 304. Connection portion104 b-1 of port 104 may be connected to a source of fluid to allow fluidto flow through lumen 104 b, lumen 104 a, middle elongate member 202,lumen 310 of elongate member 304, and out orifice 306. The fluid may beany suitable fluid for irrigating body tissue.

When medical device 1 is disposed in the desired position substantiallyadjacent to tissue to be removed, medical device 1 may be operated.Specifically, tip 305 may be used to hook, lift, and position tissue forexcision. This may be necessary where, in some instances, the tissue tobe removed may be folded over so as to make it difficult, if notimpossible, to get elongate member 304 underneath the tissue. In suchcases, tip 305 may be used by placing tip 305 underneath the tissue andthen using the tip 305 to raise the tissue. This may be called hooking.Tip 305 may be configured to hook tissue, for example, by having abeveled edge configured to assist in getting underneath the folded overtissue. Once the tissue is raised, elongate member 304 may be used tocut the tissue. In other cases, fluid may be supplied to lumen 104 b,lumen 104 a, lumen 202 c of middle elongate member 202, lumen 310 ofelongate member 304, and orifice 306 via a source of fluid connected toconnection portion 104 b-1 of port 104. Fluid may be ejected distallyout of orifice 306 and underneath the tissue so as to raise the tissueto be cut. Fluid may also be ejected to clear blood and/or other bodilyfluids from the tissue site so as to allow for accurate manipulation ofthe tissue. Once raised, elongate member 304 may be used to cut thetissue. Any other suitable method of raising the tissue, such as byneedle injection of fluid, may be used.

A user then may cause capsule 303 to move proximally so as to exposeelongate member 304 and substantially cover capsule 303 (or at leastfirst and second sections 307, 308) with sheath 302. Capsule 303 may bemoved proximally by moving actuator 102 proximally along guide shaft 106toward thumb ring 105 of handle 101. Actuator 102 may be movedproximally by a user placing fingers in finger rings 107 and a thumb inthumb ring 105, and then bringing the finger rings 107 and thumb ring105 closer together. Moving actuator 102 proximally may cause connector103, elongate portion 113, and elongate connectors 203 to also moveproximally. The outer surface of elongate portion 113 may cooperate withinner surface 106 b of guide shaft 106 and O-ring 114 to substantiallyprevent fluid from flowing from lumen 104 a proximal to proximal end 104c of port 104 and O-ring 114. Similarly, the outer surface of elongateconnectors 203 may cooperate with an inner surface of lumens 301 a, 301c to substantially prevent fluid from flowing from lumen 202 c to anarea surrounding elongate portion 304. Movement of elongate connectors203 proximally may cause capsule 303 to move proximally due to theirattachment to capsule 303 at second section 308. Capsule 303 may bemoved proximally until a proximal end of first section 307 comes intocontact with a distal end of cap 301 and/or when a portion of actuator102 disposed in slot 110 contacts a proximal end of slot 110.

Current may be then supplied to elongate member 304 and second section308 via a source of current connected to connector 103 and elongateconnectors 203. Specifically, a monopolar current may flow from thesource of current to elongate connectors 203, to cap 301, and then toelongate member 304 when elongate member 304 contacts tissue. Becausesecond section 308 is covered by sheath 302, even though second section308 is connected to elongate connectors 203, current does not flowthrough second section 308 at this time because a circuit cannot becompleted without second section 308 being in contact with body tissue.

With or without current, elongate member 304 may be used to cut tissueusing any suitable technique. One method may involve placing the tissueto be removed to one side of elongate member 304, and then manipulatingelongate member 304 so as to cut through the tissue to be removed.Another method may involve moving elongate member 304 laterally orcircumferentially in a given direction of resection.

Once tissue is removed, the remaining tissue may bleed. In such cases,capsule 303 may be advanced distally out of sheath 302 so as to exposecapsule 303, at least second section 308 and third section 309. Capsule303 may be advanced longitudinally distally by moving distally elongateconnectors 203, connector 103, actuator 102, and finger rings 107relative to thumb ring 105, guide shaft 106, port 104, outer elongatemember 201, middle elongate member 202, inner elongate member 204,sheath 302, cap 301, elongate member 304, tip 305, and orifice 306.

Current may be supplied to second section 308. Specifically, when secondsection 308 contacts tissue, current may flow from elongate connectors203, through second section 308, and to the body tissue with whichsecond section 308 is in contact. Thus, when second section 308 is incontact with the bleeding tissue, current may be applied to the tissueso as to cauterize the tissue and stop or at least substantially reducethe bleeding. At this time, because capsule 303 prevents elongateportion 304 from contacting body tissue, current may not flow throughelongate portion 304 even though elongate portion 304 is electricallyconnected to elongate connectors 203 via cap 301.

There may be other variations in embodiments of the invention. Forexample, the endoscope and device 1 may be placed into any tortuous bodylumen of a patient. The endoscope and device 1 may be advancedseparately or together. Any suitable portion of the endoscope and device1 may be substantially adjacent to body tissue to be removed. Medicaldevice 1 may be connected to a source of current and/or a source offluid at any point in time, and cautery or irrigation may be supplied atany suitable point in the procedure. At any point, therefore, anyportion of medical device 1 may be in the active or passiveconfiguration. Device 1 may be used without an endoscope. For example, aseparate visual device may be placed adjacent to device 1 in the body.

Any of the steps set forth herein may be repeated as many times asnecessary and/or implemented in any particular order. For example, atissue portion may be removed using elongate member 304, the remainingtissue may be cauterized using second section 308, and then anothertissue portion may be removed followed by cauterization. The tissue maybe irrigated at any point in any of these steps set forth herein. Thesesteps may be performed at substantially the same tissue site (e.g.,multiple cuts, cauterizations, and/or irrigations may be necessary toremove a single piece of tissue) or at different tissue sites (e.g.,medical device 1 may be repositioned in the body lumen so as to removedifferent tissue portions). An advantage of embodiments of the inventionmay be that tissue may be removed, cauterized, and/or irrigated using asingle medical device 1 that does not need to be removed from the bodylumen during the procedure.

In another embodiment, as shown in FIG. 4 , distal portion 1300 mayinclude a capsule 1303 and an elongate member 1304 each having a bipolarconfiguration. Other portions of such a medical device may be modifiedto accommodate this bipolar configuration. Capsule 1303 may have firstsection 1303 a, second section 1303 b, third section 1303 c, fourthsection 1303 d, and fifth section 1303 e. Second section 1303 b andfourth section 1303 d may be comprised of conductive material and may beconfigured to pass a bipolar current therethrough, whether or not thesesections are in contact with tissue, while first section 1303 a, thirdsection 1303 c, and fifth section 1303 e may be comprised of insulativematerial and may be configured to insulate second section 1303 b andfourth section 1303 d from each other and surrounding structure. Bipolarcurrent may be provided to both of second section 1303 b and fourthsection 1303 d via elongate connectors to enable bipolar cauterization,whether or not these sections are in contact with tissue.

In the same embodiment, elongate member 1304 may have first section 1304a, second section 1304 b, third section 1304 c, fourth section 1304 d,and fifth section 1304 e. Second section 1304 b and fourth section 1304d may be comprised of conductive material and may be configured to passa bipolar current therethrough, whether or not these sections are incontact with tissue, while first section 1304 a, third section 1304 c,and fifth section 1304 e may be comprised of insulative material and maybe configured to insulate second section 1304 b and fourth section 1304d from each other and surrounding structure. Bipolar current may beprovided to both of second section 1304 b and fourth section 1304 d viaelongate connectors to enable bipolar current for excision of tissue,whether or not these sections are in contact with tissue.

In a further example, as shown in FIG. 5 , a capsule 2303 may have afirst section 2303 a and a second section 2303 b. Each of first section2303 a and second section 2303 b may have a substantially complementaryhelical configuration, and second section 2303 b may be configured topass a monopolar current therethrough when second section 2303 b is incontact with tissue, while first section 2303 a may be configured toinsulate various portions of second section 2303 b longitudinallyseparated by corresponding portions of first section 2303 a. Monopolarcurrent may be provided to second section 2303 b via the elongateconnectors 203 when second section 2303 b is in contact with tissue.

In yet another example, as shown in FIG. 5 , an elongate member 2304(e.g., a cutting member) may have a first section 2304 a and a secondsection 2304 b. Each of first section 2304 a and second section 2304 bmay have a substantially complementary helical configuration, and secondsection 2304 b may be configured to pass a monopolar currenttherethrough when second section 2304 b is in contact with tissue, whilefirst section 2304 a may be configured to insulate various portions ofsecond section 2304 b longitudinally separated by corresponding portionsof first section 2304 a. Monopolar current may be provided to secondsection 2304 b via the elongate connectors 203 when second section 2304b is in contact with tissue.

In various embodiments, capsule 1303, 2303 and elongate member 1304,2304 may have any number of current conducting and insulating sectionsin any suitable shape and/or combination. Current may be provided to theappropriate portions of capsule 1303, 2303 and elongate member 1304,2304 using any suitable method, for example, via elongate connectors203.

Other embodiments of the invention will be apparent to those skilled inthe art from consideration of the specification and practice of theinvention disclosed herein. It may be intended that the specificationand examples be considered as exemplary only, with the true scope andspirit of the invention being indicated by the following claims.

1.-41. (canceled)
 42. A medical device, comprising: a handle including an electrical connection and an actuator; a shaft coupled to the handle, the shaft including an electrical connector coupled to the electrical connection; a sheath coupled to the shaft, wherein the sheath includes an end having an opening, and the sheath further includes a conductive portion and an insulative portion; a cap adjacent to a portion of the sheath; and an electrode coupled to the electrical connector, wherein the electrode includes a body and a distal tip, wherein the distal tip is insulative, and wherein a distal end of the cap is configured to limit further retraction of the sheath relative to the electrode and the cap as a proximal end of the sheath abuts the distal end of the cap.
 43. The medical device of claim 42, wherein the body of the electrode has a cylindrical and electrically-conductive outer surface.
 44. The medical device of claim 42, wherein the opening is the sole opening in the end of the sheath.
 45. The medical device of claim 42, wherein the distal tip is enlarged relative to the body such that the distal tip protrudes radially outwardly relative to the body, and wherein a proximal portion of the body includes an insulative section.
 46. The medical device of claim 42, wherein a gap is formed between an outer surface of the body of the electrode and an inner surface of the sheath where the sheath surrounds the electrode.
 47. The medical device of claim 42, wherein the insulative portion of the sheath is adjacent to the conductive portion of the sheath.
 48. The medical device of claim 42, wherein the sheath is configured to longitudinally translate relative to the electrode and the cap.
 49. The medical device of claim 42, wherein the distal tip further includes a proximal-facing end face, and wherein the proximal-facing end face is configured to abut the sheath when the sheath is longitudinally translated relative to the electrode, thereby inhibiting further proximal movement of the electrode relative to the sheath.
 50. A medical device, comprising: a shaft including an electrical connector; a cap coupled to an end of the shaft; a sheath adjacent to the cap, wherein the sheath includes a distal end having an opening; an electrode, including: a proximal portion coupled to the electrical connector, wherein a portion of the proximal portion is insulative, and a distal portion at a distal end of the proximal portion, wherein the distal portion is enlarged relative to the proximal portion, and wherein the distal portion is insulative, wherein the sheath includes a conductive segment and an insulative segment, and wherein the sheath is configured to longitudinally translate relative to the cap and the electrode, and wherein a distal end of the cap is configured to limit further retraction of the sheath relative to the electrode and the cap.
 51. The medical device of claim 50, wherein the proximal portion of the electrode is a cylindrical rod extending through an opening of the cap and the opening of the sheath.
 52. The medical device of claim 50, wherein the sheath is configured to move proximally and distally relative to the cap by actuation of an actuator.
 53. The medical device of claim 50, wherein the insulative proximal portion is a cylindrical segment of the proximal portion.
 54. The medical device of claim 50, wherein a distal end of the distal portion is atraumatic.
 55. The medical device of claim 50, wherein the distal portion further includes a proximal-facing end face, and wherein the proximal-facing end face is configured to abut the sheath when the electrode is in a retracted position relative to the sheath, thereby inhibiting further proximal movement of the electrode relative to the sheath.
 56. A medical device, comprising: a handle including an electrical connection; a shaft coupled to the handle, the shaft including an electrical connector coupled to the electrical connection; a sheath coupled to the shaft; and a conductive member, including: insulating portions surrounding portions of the conductive member, and a distal portion at a distal end of the proximal portion, wherein the distal portion is enlarged relative to the proximal portion such that the distal portion protrudes radially outwardly relative to the proximal portion, the distal portion including a distal-facing end face, and wherein the distal portion is insulative, wherein the sheath includes a conductive segment and an insulative segment adjacent to the conductive segment, and wherein the sheath is configured to longitudinally translate relative to the conductive member and the shaft.
 57. The medical device of claim 56, wherein the proximal portion of the conductive member has a cylindrical outer surface.
 58. The medical device of claim 56, wherein the insulative segment of the proximal portion is cylindrical.
 59. The medical device of claim 56, wherein the sheath is configured to surround the insulative segment of the proximal portion.
 60. The medical device of claim 56, wherein the distal portion further includes a proximal-facing end face, and wherein the proximal-facing end face is configured to abut the sheath when the electrode is in a retracted position relative to the sheath, thereby inhibiting further proximal movement of the conductive member relative to the sheath.
 61. The medical device of claim 56, wherein the proximal portion of the conductive member has a constant width. 